CN115425661A - Power supply system, power oscillation suppression method for power supply system, and power system - Google Patents

Power supply system, power oscillation suppression method for power supply system, and power system Download PDF

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Publication number
CN115425661A
CN115425661A CN202211048934.3A CN202211048934A CN115425661A CN 115425661 A CN115425661 A CN 115425661A CN 202211048934 A CN202211048934 A CN 202211048934A CN 115425661 A CN115425661 A CN 115425661A
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China
Prior art keywords
power
power supply
oscillation
controller
output
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CN202211048934.3A
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Chinese (zh)
Inventor
王淑超
王君超
曲文强
万松
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Huawei Digital Power Technologies Co Ltd
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Huawei Digital Power Technologies Co Ltd
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Priority to CN202211048934.3A priority Critical patent/CN115425661A/en
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    • H—ELECTRICITY
    • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02J—CIRCUIT ARRANGEMENTS OR SYSTEMS FOR SUPPLYING OR DISTRIBUTING ELECTRIC POWER; SYSTEMS FOR STORING ELECTRIC ENERGY
    • H02J3/00—Circuit arrangements for ac mains or ac distribution networks
    • H02J3/002—Flicker reduction, e.g. compensation of flicker introduced by non-linear load
    • H—ELECTRICITY
    • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02J—CIRCUIT ARRANGEMENTS OR SYSTEMS FOR SUPPLYING OR DISTRIBUTING ELECTRIC POWER; SYSTEMS FOR STORING ELECTRIC ENERGY
    • H02J3/00—Circuit arrangements for ac mains or ac distribution networks
    • H02J3/24—Arrangements for preventing or reducing oscillations of power in networks
    • H—ELECTRICITY
    • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02J—CIRCUIT ARRANGEMENTS OR SYSTEMS FOR SUPPLYING OR DISTRIBUTING ELECTRIC POWER; SYSTEMS FOR STORING ELECTRIC ENERGY
    • H02J3/00—Circuit arrangements for ac mains or ac distribution networks
    • H02J3/38—Arrangements for parallely feeding a single network by two or more generators, converters or transformers
    • H02J3/46—Controlling of the sharing of output between the generators, converters, or transformers
    • H—ELECTRICITY
    • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02J—CIRCUIT ARRANGEMENTS OR SYSTEMS FOR SUPPLYING OR DISTRIBUTING ELECTRIC POWER; SYSTEMS FOR STORING ELECTRIC ENERGY
    • H02J3/00—Circuit arrangements for ac mains or ac distribution networks
    • H02J3/38—Arrangements for parallely feeding a single network by two or more generators, converters or transformers
    • H02J3/46—Controlling of the sharing of output between the generators, converters, or transformers
    • H02J3/48—Controlling the sharing of the in-phase component
    • H—ELECTRICITY
    • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02J—CIRCUIT ARRANGEMENTS OR SYSTEMS FOR SUPPLYING OR DISTRIBUTING ELECTRIC POWER; SYSTEMS FOR STORING ELECTRIC ENERGY
    • H02J3/00—Circuit arrangements for ac mains or ac distribution networks
    • H02J3/38—Arrangements for parallely feeding a single network by two or more generators, converters or transformers
    • H02J3/46—Controlling of the sharing of output between the generators, converters, or transformers
    • H02J3/50—Controlling the sharing of the out-of-phase component
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02E—REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION
    • Y02E10/00—Energy generation through renewable energy sources
    • Y02E10/70—Wind energy
    • Y02E10/76—Power conversion electric or electronic aspects

Abstract

The power supply system comprises a controller and one or more power supply units, wherein any power supply unit comprises a power supply assembly and power conversion equipment, the power supply assembly is connected to a grid-connected point of the power supply system through the power conversion equipment, the controller is used for collecting voltage and/or current information of the grid-connected point, the power conversion equipment of each power supply unit in the one or more power supply units is controlled to output first output power based on the power oscillation information, the power oscillation information is obtained based on the voltage and/or current information of the grid-connected point, and the first output power of any power supply unit is obtained by active and/or reactive power supplied by any power supply unit and first incremental power used for restraining regional power oscillation. By the adoption of the power supply system, the operation convenience of power oscillation suppression of the power supply system can be improved, the suppression efficiency of the power oscillation of the power supply system is improved, the system safety of the power supply system is enhanced, and the applicability is high.

Description

Power supply system, power oscillation suppression method for power supply system, and power system
Technical Field
The present application relates to the field of power electronics technologies, and in particular, to a power supply system, a power oscillation suppression method for the power supply system, and a power system.
Background
Under the guidance of a 'double-carbon' target vision that carbon reaches the peak before 2030 years and carbon is neutralized before 2060 years, a novel power system in China is in a rapid construction stage, the proportion of new energy in a power grid is gradually improved, the novel power system has an obvious 'double-high' characteristic, namely, high-proportion renewable energy is accessed to high-proportion power electronic equipment, and a new problem is brought to safe and stable operation of the novel power system. For example, obvious power oscillation phenomena including subsynchronous/supersynchronous power oscillation are found in electric power systems of a plurality of new energy electric fields (mainly wind power bases) in northwest, northeast and the like of China, and the subsynchronous/supersynchronous power oscillation becomes an important problem for safe and efficient operation of large-scale new energy electric power systems in China.
The inventor of the application finds that the capacity of the new energy electric field is continuously increased due to the large difference of the operation conditions of the electric power system of each new energy electric field in the research and practice processes, and the condition of subsynchronous/supersynchronous power oscillation brought to the electric power system of the new energy electric field by distributed new energy grid-connected access is complicated. In the prior art, a typical power oscillation suppression method is to connect primary devices such as a capacitor, an inductor, a resistor or a transformer in a circuit or a node to suppress power oscillation, and the system is complex and high in cost. Meanwhile, subsynchronous power oscillations generated by different power generation units connected to the grid in the power system of the new energy electric field are different, and the subsynchronous power oscillations of the power system are also extremely complex after the different power generation units are connected to the grid.
Disclosure of Invention
The application provides a power supply system, a power oscillation suppression method of the power supply system and a power system, which can improve the operation convenience of power oscillation suppression of the power supply system, improve the suppression efficiency of power oscillation of the power supply system, enhance the system safety of the power supply system, and have the advantages of simple operation and strong applicability.
In a first aspect, the present application provides a power supply system, where the power supply system includes a controller and one or more power supply units, where each of the one or more power supply units includes a power supply component and a power conversion device, and the power supply component in each of the power supply units is connected to a grid-connected point of the power supply system through the power conversion device. In the power supply system, the controller can collect the voltage and/or current information of the grid-connected point, and the controller can be directly connected with the grid-connected point to collect the voltage and/or current information of the grid-connected point and can support the access of the instantaneous value of the voltage and/or current of the grid-connected point. Optionally, the controller may also be connected to a grid-connected point through a Current Transformer (CT), and may support current access with a current rating of 1A or 5A. The controller can also support voltage access with a voltage rated value of 100V to 1000V through a Potential Transformer (PT), and can support interval voltage to avoid PT direct access, so that the operation is flexible and the applicability is strong. The controller may control the power conversion device of each of the one or more power supply units to output the first output power based on the power oscillation information, where the power oscillation information is obtained based on the voltage and/or current information of the grid-connected point, and the first output power of any power supply unit may be obtained from the active and/or reactive power supplied by any power supply unit and the first incremental power for suppressing the area power oscillation. In the application, the controller can directly detect the voltage and/or current information of the grid-connected point of the power supply system to monitor the local power oscillation information of the power supply system, and further can control the power conversion equipment of each power supply unit in the power supply system to output the output power for inhibiting the local power oscillation when the local power oscillation of the power supply system is obtained, so that the inhibition of the local power oscillation of the power supply system is realized, the power oscillation in a wider range caused by the local power oscillation of the power supply system can be avoided, and the safety of power electronic equipment such as the power supply system and the like can be enhanced. In other words, the controller can control the power conversion equipment of each power supply unit to output the target output power, the control output of the target output power can meet the regulation requirement of the output power of the power conversion equipment and the suppression requirement of the power oscillation of the power supply system, the operation convenience of the power oscillation suppression of the power supply system can be improved, the suppression efficiency of the power oscillation of the power supply system is improved, the system safety of the power supply system is enhanced, the operation is simple, and the applicability is strong.
With reference to the first aspect, in a first possible implementation manner, the controller may issue a first output power control command to the power conversion device of each power supply unit. Here, the controller may analyze oscillation information of local power oscillation existing in the power supply system based on voltage and/or current information of a grid-connected point of the power supply system and obtain power oscillation suppression information such as increment power of oscillation suppression, and then, multiplex the local communication function of the power supply system to issue a control command of active power and/or reactive power facing the power oscillation suppression function, and control the power conversion device of each power supply unit to output power facing the power oscillation suppression by sending an output power control instruction to the power conversion device of each power supply unit of the power supply system, so that difficulty in system device deployment of the local power oscillation suppression of the power supply system can be reduced, and cost of the system device deployment can be reduced. In this application, the power conversion device of any power supply unit in the power supply system may output the first output power corresponding to any power supply unit in response to a first output power control instruction issued by the controller, that is, output power sufficient to suppress power oscillation, including the output power of the power conversion device and the incremental power used for suppressing power oscillation during normal operation when the power supply unit supplies power. In the application, the power conversion equipment of each power supply unit in the power supply system has the output regulation capacity of active power and reactive power required by power oscillation suppression, can replace additionally added physical equipment such as inductance, capacitance, transformer or resistance required by traditional power oscillation suppression, fully utilizes the active power and/or reactive power regulation capacity of the power supply unit, can simplify the equipment and/or circuit deployment complexity of the power oscillation suppression of the power supply system, reduces the realization difficulty of the power oscillation suppression of the power supply system, and is simple in operation and strong in applicability.
With reference to the first possible implementation manner of the first aspect, in a second possible implementation manner, the controller may report the power oscillation information to an upper-level system, where the upper-level system includes one of a power station Energy Management System (EMS), a SCADA (supervisory control and data acquisition) system, a power station power controller, a power grid panoramic monitoring system, a power grid safety and stability control system, or a power grid wide area measurement system. In the application, the power oscillation information is reported to the superior system, so that the superior system can perform comprehensive systematic power oscillation analysis, the system safety of the superior system is ensured, the working stability of the power supply system is also ensured, and the safety of the power supply system is enhanced. In addition, in the application, the reporting of the power oscillation information can improve the effective utilization rate of the power oscillation information, and further, historical power oscillation information can be deleted when the local storage capacity space of the power supply system is insufficient, so that the effective utilization rate of the storage space of the power oscillation information of the power supply system is improved, and the system safety of the power supply system is enhanced.
With reference to the first aspect or the second possible implementation manner of the first aspect, in a third possible implementation manner, the controller may receive a power oscillation suppression instruction, where the power oscillation suppression instruction carries indication information of system oscillation suppression power. Optionally, the power oscillation suppression instruction may be issued by the upper-level system, or may be sent by another power supply system connected to the power supply system in the upper-level system in a grid-connected manner, and may be specifically determined according to an actual application scenario, which is not limited herein. In this application, the controller may issue a second output power control instruction to the power conversion device of each power supply unit in the power supply system based on the indication information of the system oscillation suppression power. The power conversion device of any power supply unit in the power supply system may output the second output power for suppressing system power oscillation in response to the second output power control instruction. Here, the second output power output by any one of the power supply units may be obtained from active and/or reactive power supplied by any one of the power supply units and a second incremental power for suppressing system power oscillation, where the second incremental power is obtained from the first incremental power and/or the system oscillation suppression power. In the application, the controller can obtain the output power of the power conversion equipment in each power supply unit facing the system power oscillation suppression by combining the active and/or reactive capacity of each power supply unit based on the requirement of the system oscillation suppression power, and further can instruct the power conversion equipment of each power supply unit to output the target output power based on the issuing of the output power control instruction of the power conversion equipment of each power supply unit, wherein the target output power comprises the output power of each power supply unit for power supply and the incremental power for suppressing the local power oscillation and/or the system power oscillation, so that the system-level power oscillation suppression can be realized, the working stability and the system safety of the power supply system are enhanced, and the controller is simple to operate and high in applicability.
With reference to the first possible implementation manner of the first aspect or the second possible implementation manner of the first aspect, in a fourth possible implementation manner, each power supply unit further includes a unit controller; the controller may be configured to issue a power output scheduling instruction to the unit controller of each power supply unit, and instruct the unit controller of each power supply unit to issue the first output power control instruction or the second output power control instruction to the power conversion device of the power supply unit to which the unit controller belongs. In the application, based on the communication between the controller and the unit controllers of the power supply units, the power converter devices of the power supply units can be controlled to output the target output power by means of the unit controllers of the power supply units, at the moment, the controller can be a superior controller of the unit controller and can be adapted to controllers of application scenes such as power stations, power grids, new energy stations and the like, the expression form of the controller is more flexible, and the applicability is stronger.
With reference to the second possible implementation manner of the first aspect, in a fifth possible implementation manner, the controller may further receive a power oscillation monitoring instruction issued by the upper level system, where the power oscillation monitoring instruction is used to instruct the controller to feed back power oscillation information of a specified frequency band. The controller may further feed back the power oscillation information to the upper system when the power oscillation information is obtained and the frequency of the power oscillation information is within the designated frequency band. In the application, in consideration of the performance and resource limitations of the controller local to the power supply system, the controller does not monitor all the power oscillation information required by the superior system, and the controller monitors only part of the typical information, including part of the voltage and/or current information. The superior system can issue detection information of a designated frequency band according to the requirement of the dynamic change of the system, the controller can respond to the feedback of the power oscillation information of the designated frequency band of the superior system, the effective utilization rate of the monitoring system of the power oscillation information of the system can be improved, the suppression efficiency and the resource utilization rate of the power oscillation of the system are enhanced, and the working stability and the system safety of the power supply system and the superior system are enhanced.
With reference to any one of the first to fifth possible implementation manners of the first aspect, in a sixth possible implementation manner, the power supply system further includes a grid-connected transformer, and the power conversion devices of the power supply units are connected in parallel to the grid-connected transformer through the grid-connected point; the controller also collects input/output I/O parameters of the grid-connected transformer, and the measurement and control and/or protection of the grid-connected transformer are realized based on the I/O parameters of the grid-connected transformer and/or voltage and/or current information of grid-connected points, so that the difficulty in realizing the measurement and control and/or protection of a power supply system can be reduced, and the safety of the power supply system is enhanced.
With reference to any one of the first to fifth possible implementation manners of the first aspect, in a seventh possible implementation manner, the controller includes a first controller and a second controller, where the first controller may be configured to collect voltage and/or current information of the grid-connected point; the first controller is also used for obtaining power oscillation information of the power supply system based on the voltage and/or current information of the grid-connected point and transmitting the power oscillation information to the second controller; the second controller may be configured to control the power conversion device of each power supply unit to output the first output power of each power supply unit. In the application, the acquisition of voltage and/or current information of a grid-connected point and the control of the output power of power conversion equipment in each power supply unit are separately deployed in different controllers, and meanwhile, the first controller and the second controller can support the detection of power oscillation information of a system, so that the deployment requirements of the controllers in different product forms can be adapted, the operation is more flexible, and the applicability is stronger.
With reference to the seventh possible implementation manner of the first aspect, in an eighth possible implementation manner, the second controller is further configured to issue the first output power control instruction to the power conversion device of each of the multiple power supply units, so as to control the power conversion device of each of the multiple power supply units to output the first output power of each of the power supply units. In the application, the second controller can directly or indirectly interact with the power conversion equipment of each power supply unit through a communication network to realize the output power control of the power conversion equipment of each power supply unit, and the power conversion equipment can be adapted to the configuration deployment of products such as a source control terminal of a power supply system, and is simple to operate and high in applicability.
With reference to the seventh possible implementation manner of the first aspect or the eighth possible implementation manner of the first aspect, in a ninth possible implementation manner, the first controller and/or the second controller is configured to report the power oscillation information to a superior system. The superior system comprises one of a power station EMS, a power station SCADA system, a power station power controller, a power grid panoramic monitoring system, a power grid safety and stability control system or a power grid wide area measurement system. In the application, the first controller and/or the second controller can report the power oscillation information, so that the product selectivity and the deployment flexibility of the first controller and/or the second controller are enhanced, and the applicability is stronger.
With reference to the ninth possible implementation manner of the first aspect, in a tenth possible implementation manner, the first controller and/or the second controller are further configured to receive a power oscillation monitoring command issued by the upper-level system, where the power oscillation monitoring command is used to instruct the first controller and/or the second controller to feed back power oscillation information of a specified frequency band; the first controller and/or the second controller are further configured to feed back the power oscillation information to the upper level system when the power oscillation information is obtained and the frequency of the power oscillation information is within the specified frequency band. In the application, the first controller and/or the second controller can realize the detection of the power oscillation information and the report of the power oscillation information, so that the product selectivity and the deployment flexibility of the first controller and/or the second controller are enhanced, the realization mode of the detection and the report of the power oscillation information is more flexible, the information feedback is more timely, and the safety of a power supply system is further enhanced.
With reference to the seventh possible implementation manner of the first aspect or the eighth possible implementation manner of the first aspect, in an eleventh possible implementation manner, the first controller is further configured to collect an I/O parameter of the grid-connected transformer, and implement measurement, control and/or protection of the grid-connected transformer based on the I/O parameter of the grid-connected transformer and/or voltage and/or current information of the grid-connected point. In the application, the first controller can realize acquisition of I/O parameters of the grid-connected transformer and/or voltage and/or current information of a grid-connected point, can correspond to data collectors of power supply systems with different expression forms, does not need to additionally arrange devices for power oscillation suppression of the power supply systems, improves flexibility and efficiency of the power oscillation suppression, and is simple in structure and strong in applicability.
With reference to any one of the first to eleventh possible implementation manners of the first aspect, in a twelfth possible implementation manner, the power supply assembly includes at least one of a photovoltaic array, a wind power supply assembly, or an energy storage battery, and the power conversion device includes at least one of a photovoltaic inverter, a wind power converter, or an energy storage converter. In other words, the power supply system provided by the application can be a photovoltaic system, a wind power generation system, a light storage power generation system, a wind power plant, a microgrid and the like, the power supply components and the corresponding power conversion equipment in different application scenes or product forms can also be configured adaptively, and the power supply system is flexible to operate and high in applicability.
With reference to any one of the first to the twelfth possible implementation manners of the first aspect, in a thirteenth possible implementation manner, the controller includes one of a subarray unit data collector, a box transformer substation measurement and control device, a source control terminal, a new energy panoramic monitoring terminal, a box transformer substation all-in-one measurement and control device, a power station power controller, a power station coordination controller, a power station frequency modulation device, a power station fast power control device, a source grid load coordination device, a microgrid controller, or a microgrid coordination control device. In this application, the controller can be photovoltaic system, wind power generation system, light stores up power generation system, photovoltaic power plant, light stores up power plant, energy storage power plant, the controlgear among power supply systems such as wind-powered electricity generation field and microgrid, also can integrate in photovoltaic system, wind power generation system, light stores up power generation system, photovoltaic power plant, light stores up power plant, energy storage power plant, a functional module of controlgear among power supply systems such as wind-powered electricity generation field and microgrid, the configuration that need not additionally to increase hardware equipment reduces power supply system's equipment configuration cost, the product competitiveness and the suitability of reinforcing controller.
In a second aspect, the present application provides a power oscillation suppression method for a power supply system, where the method is applied to a controller of the power supply system provided in any one of the first to twelfth possible implementation manners of the first aspect, and the method includes: collecting voltage and/or current information of a grid-connected point of a power supply system; controlling power conversion equipment of each power supply unit in one or more power supply units connected in a grid-connected mode in a power supply system to output first output power based on the power oscillation information; the power oscillation information is obtained based on the voltage and/or current information of the grid-connected point, and the first output power of any power supply unit is obtained by the active and/or reactive power supplied by any power supply unit and the first incremental power for restraining regional power oscillation. In the application, the output power for suppressing the local power oscillation is output by controlling the power conversion equipment of each power supply unit in the power supply system, so that the suppression of the local power oscillation of the power supply system can be realized, the power oscillation in a wider range caused by the local power oscillation of the power supply system can be avoided, the operation convenience of suppressing the power oscillation of the power supply system can be improved, the suppression efficiency of the power oscillation of the power supply system is improved, the system safety of the power supply system is enhanced, the operation is simple, and the applicability is strong
With reference to the second aspect, in a first possible implementation manner, in the method, when the power conversion device of each of the one or more power supply units connected to the power supply system in a grid-connected manner is controlled to output the first output power, a first output power control instruction may be issued to the power conversion device of each of the one or more power supply units connected to the power supply system in a grid-connected manner, and the power conversion device of each power supply unit is triggered to output the first output power of each power supply unit in response to the first output power control instruction based on the first output power control instruction. In the application, the control command of the active power and/or the reactive power facing the power oscillation suppression function is issued by multiplexing the local communication function of the power supply system, and the output power control command is sent to the power conversion equipment of each power supply unit of the power supply system to control the power conversion equipment of each power supply unit to output the output power facing the power oscillation suppression, so that the deployment difficulty of the system equipment for the local power oscillation suppression of the power supply system can be reduced, and the deployment cost of the system equipment is reduced.
With reference to the second aspect or the first possible implementation manner of the first aspect, in a second possible implementation manner, the method may further report the power oscillation information to the upper-level system. Here, the upper-level system includes one of a power station EMS, a power station SCADA system, a power station power controller, a power grid panorama monitoring system, a power grid security and stability control system, or a power grid wide area measurement system. In the application, the power oscillation information is reported to the superior system, so that the superior system can perform comprehensive systematic power oscillation analysis, the system safety of the superior system is ensured, the working stability of the power supply system is also ensured, and the safety of the power supply system is enhanced. In addition, in the application, the reporting of the power oscillation information can improve the effective utilization rate of the power oscillation information, and further can delete the historical power oscillation information when the local storage capacity space of the power supply system is insufficient, so that the effective utilization rate of the storage space of the power oscillation information of the power supply system is improved, and the system safety of the power supply system is enhanced.
With reference to the second possible implementation manner of the second aspect, in a third possible implementation manner, the method further includes: receiving a power oscillation suppression instruction, wherein the power oscillation suppression instruction carries indication information of system oscillation suppression power; and issuing a second output power control instruction to the power conversion equipment of each power supply unit based on the indication information of the system oscillation suppression power, triggering the power conversion equipment of each power supply unit to respond to the second output power control instruction based on the second output power control instruction, and outputting second output power for suppressing system power oscillation. Here, the second output power of any power supply unit is derived from the active and/or reactive power supplied by any power supply unit and a second incremental power for suppressing system power oscillation, wherein the second incremental power is derived from the first incremental power and/or the system oscillation suppression power. In the application, the power conversion equipment of each power supply unit is instructed to output the target output power based on the issuing of the output power control instruction of the power conversion equipment of each power supply unit, and the target output power comprises the output power supplied by each power supply unit and the incremental power used for restraining local power oscillation and/or system power oscillation, so that the system-level power oscillation restraining can be realized, the working stability and the system safety of a power supply system are enhanced, and the power conversion equipment is simple to operate and high in applicability.
With reference to the second possible implementation manner of the second aspect or the third possible implementation manner of the second aspect, in a fourth possible implementation manner, the method further includes: and issuing a power output scheduling instruction to the unit controller of each power supply unit, and instructing the unit controller of each power supply unit to issue the first output power control instruction or the second output power control instruction to the power conversion equipment of the power supply unit, so that the realization flexibility of power suppression can be improved, and the applicability is stronger.
With reference to any one of the first possible implementation manner to the fourth possible implementation manner of the second aspect, in a fifth possible implementation manner, the method further includes: receiving a power oscillation monitoring instruction issued by an upper-level system, wherein the power oscillation monitoring instruction is used for indicating the controller to feed back power oscillation information of a specified frequency band; and when the power oscillation information is obtained and the frequency of the power oscillation information is in the designated frequency band, reporting the power oscillation information to the superior system. In the application, in consideration of local controller performance and resource limitations of the power supply system, the controller of the power supply system does not monitor all power oscillation information required by the superior system, and generally the controller monitors only part of typical information, including part of voltage and/or current information. The superior system can issue detection information of a designated frequency band according to the requirement of the dynamic change of the system, the power supply system can respond to the feedback of the power oscillation information of the designated frequency band of the superior system, the effective utilization rate of the monitoring system of the power oscillation information of the system can be improved, the suppression efficiency and the resource utilization rate of the power oscillation of the system are enhanced, and the working stability and the system safety of the power supply system and the superior system are enhanced.
In a third aspect, the present application provides an electrical power system, where the electrical power system includes a plurality of control systems and the power supply system provided in any one of the first to twelfth possible implementation manners of the first aspect. Here, the power system may be a centralized access power system of a new energy station (including a wind farm and/or a solar power station), a centralized access power system of an energy storage power station, a centralized access power system of a light storage power station or a wind storage power station, and the like, each power supply system in the power system may be accessed in parallel through a grid-connected point, each power supply system may also be accessed in parallel through a grid-connected transformer, and the plurality of power supply systems may supply power to loads such as a power grid, power electronic devices, and the like after being connected in parallel. The control system can comprise a power station EMS, a power station SCADA system, a power station power controller, a power grid panoramic monitoring system, a power grid safety and stability control system, or a power grid wide area measurement system and the like, can realize system-level power oscillation monitoring and suppression of the power system based on power oscillation information reported by each power supply system, enhances the power supply stability and the system safety of the power system, and has a simple structure and strong applicability.
Drawings
Fig. 1 is a schematic view of an application scenario of an electric power system provided in an embodiment of the present application;
fig. 2 is a schematic structural diagram of an electric power system provided in an embodiment of the present application;
FIG. 3 is another schematic structural diagram of an electrical power system provided in an embodiment of the present application;
fig. 4 is a schematic structural diagram of a power supply system provided in an embodiment of the present application;
fig. 5 is another schematic structural diagram of a power supply system provided in an embodiment of the present application;
fig. 6 is another schematic structural diagram of a power supply system provided in an embodiment of the present application;
fig. 7 is a schematic flowchart of a power oscillation suppression method of a power supply system according to an embodiment of the present application.
Detailed Description
With the proposal of the 'double-carbon' target, an electric power system with new energy (photovoltaic, wind power and the like) centralized access increasingly presents obvious 'double-height' characteristics, and meanwhile, with the large-scale access of the new energy to the power grid, the power grid also meets more and more challenges, wherein conventional new energy control modes such as rough skip-cutting of a new energy collection line, skip-cutting of a new energy power station, regulation delay reaching the minute level and the like in the control of the new energy accessed to the power grid are more and more difficult to meet the requirements of the power grid. Meanwhile, with the increase of the capacity of the new energy station accessed by the power grid, the safety risk of the power system caused by improper operation in the control of the new energy station is increased, so that the demand of rapidly monitoring the new energy station before, during and after an accident of new energy (especially wind power and photovoltaic) energy storage is shown. The method is characterized in that the operation state of all equipment below a grid-connected point of a new energy station (including a wind power station or a photovoltaic station (or called a photovoltaic power station) which is connected to a power system in a centralized manner, including but not limited to a grid-connected transformer, a bus, a circuit, a converter (a wind power converter and/or an energy storage converter), an energy storage battery, a wind power generator set, photovoltaic power generation equipment, reactive power regulation equipment, auxiliary equipment and the like) is comprehensively mastered, the full-process monitoring and control (or panoramic monitoring for short) of the functions of controllable resource monitoring, real-time tracking, lean fine control and the like of the new energy station side are realized, the management efficiency and the safety of the new energy station can be improved, and the consumption level of new energy can be further improved.
Generally, a source control terminal (i.e., an Intelligent Electronic Device (IED)) needs to be installed on an inverter side of a light storage station (i.e., a photovoltaic/energy storage station) or a wind turbine side of a wind power station to achieve panoramic monitoring of a new energy station, and information acquisition and analysis of sub/super-synchronous power oscillation are performed on the light storage station or the wind power station based on the source control terminal. For a photovoltaic/energy storage station using a centralized inverter and/or converter, each centralized inverter and/or converter in the photovoltaic/energy storage station needs to be configured with one source control terminal, and one source control terminal is installed corresponding to each box transformer (i.e., a box-type substation) of the photovoltaic/energy storage station. For a photovoltaic/energy storage station using a string inverter, each inverter square matrix and/or converter square matrix needs to be configured with one source control terminal, and similarly, one source control terminal is installed corresponding to each box transformer of the photovoltaic/energy storage station. For a wind power station, each fan needs to be configured with a source control terminal, and one source control terminal is installed corresponding to each box transformer substation in the wind power station. The source control terminal realizes fast communication with an inverter and/or a converter (comprising a wind power converter and/or an energy storage converter) from below and realizes communication with a centralized control device of the new energy station from above. According to the scale of wind power stations, photovoltaic stations and energy storage stations, panoramic monitoring is generally realized in each station, and dozens or even hundreds of source control terminals are required to be installed in a panoramic monitoring system. In the aspect of equipment installation and deployment, existing equipment and installation problems in a subarray also need to be considered, and a subarray unit data collector (short for data acquisition), a box transformer substation measurement and control (box transformer substation protection and box transformer substation measurement and control independent configuration or integrated configuration, for convenience of description, hereinafter referred to as box transformer substation measurement and control) device is usually installed in a power generation unit of an optical storage station in a new energy station; wind power stations are slightly different, box transformer substation measurement and control devices are also arranged in the power generation units, data acquisition equipment for data acquisition of multiple equipment is not provided, and the main control equipment of the wind power stations can meet the requirements of wind power data interactive control. For a new energy station, a new energy panoramic monitoring system needs to be deployed, a source control terminal needs to be installed, according to the actual engineering requirements of the new energy station, a general source control terminal needs to be installed on the low-voltage side of a box transformer substation, however, the installation position of the source control terminal is not reserved in the box transformer substation provided by a box transformer substation manufacturer, only the installation positions of equipment such as box transformer substation measurement and control are needed, the source control terminal is only installed in a newly-added outdoor box (a fan can also select a fan tower barrel), the outdoor box transformer substation needs to be produced and customized again, and a voltage cable and a current cable need to be laid from the low-voltage side of the box transformer substation to the installation position of the source control terminal for collecting voltage and current. In addition, a network cable is required to be laid, the source control terminal is communicated with equipment such as an inverter, a converter and/or data acquisition in the power generation unit, related optical fiber networking is carried out, the number of devices of the new energy station and construction investment cost are increased, the structure is complex, and the applicability is low. Meanwhile, besides the above requirements of providing an installation position, supplying power and laying related cables and network cables for the source control terminal, for operation and maintenance personnel of the new energy station, operation and maintenance of the subarray data acquisition and box transformer substation measurement and control device are required, and operation and maintenance of the source control terminal are also required, so that operation and maintenance workload is increased.
In addition, the current subsynchronous power oscillation suppression device of the new energy station is often fixed on the whole station side of a large power station or in a power transmission line in a centralized manner, and the subsynchronous power oscillation of all lines in the new energy station is suppressed in a centralized manner, and a suppression manner is to adopt relatively large primary equipment such as a resistor, an inductor, a capacitor or a transformer connected in the line or a node, and sometimes to use power electronic equipment such as an Insulated Gate Bipolar Transistor (IGBT) in a matched manner to suppress the power oscillation.
The power supply system provided by the embodiment of the application can be intensively accessed to the power system of the new energy station, the power supply system can meet the power oscillation detection and suppression problems of the local new energy power generation unit, the relevant data (such as voltage and/or current information of power oscillation) of the power oscillation can be reported to the superior system (namely the power system of the new energy station), meanwhile, the power oscillation suppression instruction of the superior system can be received, the system-level power oscillation suppression of the superior system can be responded, the power oscillation suppression requirements of the region and/or the system level are met, the implementation difficulty is low, and the applicability is strong. Meanwhile, the power supply system can be used as a subarray of the power system of the new energy station to automatically detect and suppress power oscillation, the probability of system-level power oscillation of the new energy station can be reduced, the configuration cost of primary equipment for suppressing the power oscillation in power grid system-level power oscillation suppression is reduced, the stability and the economy of the power system are improved, the operation is simple, and the applicability is high.
The power system provided by the embodiment of the application is suitable for a new energy station, the power system can be a centralized access power system of the new energy station (comprising a wind power plant and/or a photovoltaic station), the centralized access power system of an energy storage power station, the centralized access power system of a light storage power station or a wind storage power station and the like, each power supply system in the power system can be accessed in parallel through a grid-connected point, each power supply system can also be accessed in parallel through a grid-connected transformer, and the plurality of power supply systems are accessed in parallel (namely connected in parallel) and then supply power to loads such as a power grid and power electronic equipment. Referring to fig. 1, fig. 1 is a schematic view of an application scenario of a power system provided in an embodiment of the present application. As shown in fig. 1, the power system may be accessed by one or more power supply systems in a grid-connected manner, and supplies power to the power grid after the one or more power supply systems are accessed in the grid-connected manner, where any one of the one or more power supply systems may be obtained by connecting one or more power supply units in parallel. As shown in fig. 1, a power supply system may be obtained by connecting one (or more) photovoltaic power supply units, one (or more) wind power supply units, and/or one (or more) energy storage power supply units in parallel. Optionally, a power supply system may also be obtained by connecting one or more photovoltaic power supply units in parallel (e.g., a photovoltaic power station), or by connecting one or more wind power supply units in parallel (e.g., a wind power station), or by connecting one or more energy storage power supply units in parallel (e.g., an energy storage power station), or by connecting one or more photovoltaic power supply units and energy storage power supply units in parallel (e.g., a light energy storage power station), or by connecting one or more wind power supply units and energy storage power supply units in parallel (e.g., a wind energy storage power station), or by connecting one or more photovoltaic power supply units and wind power supply units in parallel (e.g., a new energy station), which may be determined according to an actual application scenario, and is not limited herein.
In some possible embodiments, as shown in fig. 1, the pv power supply unit includes at least a pv power supply component (e.g., a pv array) and a power conversion device (e.g., a pv inverter), and the pv array is connected to a grid-connected point (not shown) through the pv inverter and/or connected to a grid-connected transformer through the grid-connected point. The photovoltaic inverter can perform inversion conversion on direct current output by the photovoltaic array and output alternating current obtained after inversion conversion to a grid-connected transformer and/or a power grid. The photovoltaic array can be formed by connecting one or more photovoltaic strings in parallel, and one photovoltaic string can be formed by connecting one or more photovoltaic modules in series. The energy storage power supply unit at least comprises an energy storage battery and an energy storage converter, the output end of the energy storage battery can be connected with one end of the energy storage converter, and the other end of the energy storage converter is connected with a grid-connected point and/or is connected with the low-voltage side of the grid-connected transformer through the grid-connected point. In a power supply system with a photovoltaic power supply unit and an energy storage power supply unit connected in parallel, an energy storage converter can perform inversion conversion on direct current provided by an energy storage battery and output alternating current obtained after the inversion conversion to a grid-connected transformer and/or a power grid. The grid-connected transformer can convert the voltage of alternating current provided by the photovoltaic inverter and/or alternating current provided by the energy storage converter and then supply power to electric equipment such as a storage battery, a communication base station or household equipment in an alternating current power grid.
In some possible embodiments, as shown in fig. 1, the wind power supply unit at least includes a wind power generation assembly (such as a wind power generator or a wind power generator set) and a wind power converter, and the wind power converter may perform voltage conversion on alternating current provided by the wind power generation assembly (may be that direct current is obtained by rectifying alternating current provided by the wind power generation assembly, and then the rectified direct current is subjected to inversion conversion to obtain alternating current after voltage conversion), and output the alternating current after voltage conversion to a grid-connected point and/or a grid-connected transformer. In a power supply system with a photovoltaic power supply unit, a wind power supply unit and/or an energy storage power supply unit connected in parallel, a grid-connected transformer can perform voltage conversion on alternating current provided by a photovoltaic inverter, alternating current provided by a wind power converter and/or alternating current provided by an energy storage converter and then supply power to storage batteries, communication base stations or household equipment and other electric equipment in an alternating current power grid.
In the embodiment of the application, the power system can be accessed to a power grid in parallel through one or more power supply systems to supply power, so that the power supply stability and the power supply efficiency of the power system can be improved, meanwhile, the power system can also receive power oscillation information reported by each power supply system based on a control system (not shown in fig. 1), and the power oscillation monitoring and suppression of the power system can be realized based on the power oscillation information reported by each power supply system, so that the system-level stability and the system safety of the power system are enhanced, and the power system is simple in structure and high in applicability. The control system can comprise a power station EMS, a power station SCADA system, a power station power controller, a power grid panoramic monitoring system, a power grid safety and stability control system, a power grid wide area measurement system and the like, can be adapted to the requirements of different product forms of different application scenes of the panoramic monitoring system or/and a source control terminal, a centralized control device of a new energy station, large-scale power station equipment, power grid equipment and the like in the new energy station, and is simple in structure and high in applicability.
Referring to fig. 2, fig. 2 is a schematic structural diagram of an electrical power system provided in an embodiment of the present application. As shown in fig. 2, a controller may be deployed in each power supply system centrally connected to the power system, where the controller may be a sub-array controller (such as a box-type substation controller) of the power supply system, and the controller may also be a centralized controller (such as a power station controller, etc.) of the power supply system, or a main controller, and for convenience of description, the controller is taken as an example and will be described below. The controller of the power supply system can directly detect voltage and/or current information of a grid-connected point of the power supply system to monitor local power oscillation information of the power supply system, and further can control power conversion equipment (including a photovoltaic inverter, a wind power converter and/or an energy storage converter) of each power supply unit in the power supply system to output power for inhibiting local power oscillation when the local power oscillation of the power supply system is obtained, so that the local power oscillation of the power supply system is inhibited, further, larger-range power oscillation caused by the local power oscillation of the power supply system can be avoided, and the safety of the power supply system and the power system can be enhanced.
In some feasible embodiments, when the controller obtains the local power oscillation information of the power supply system, the controller also reports the power oscillation information to the upper-level system, where the upper-level system may be a control system of the power system, including but not limited to the power station EMS, the power station SCADA system, the power station power controller, the power grid panoramic monitoring system, the power grid safety and stability control system, the power grid wide area measurement system, and the like, which may be specifically determined according to an actual application scenario, and is not limited herein. It is understood that the representation of the controller may be different in each power supply system of the power system, in different types of power supply systems or in different power supply units of the power supply system. Referring to table 1, table 1 is a schematic table of product forms of controllers and objects collected and/or controlled by the controllers in a power supply system of a power system. As shown in table 1, in the photovoltaic station power generation unit, the energy storage power station power generation unit, the optical energy storage station power generation unit, the wind power storage power generation unit, the optical wind power storage power generation unit, or the optical wind power storage power generation unit, the power supply system may be a photovoltaic power supply system in which a plurality of photovoltaic power supply units are connected in a grid-connected manner, an energy storage power supply system in which a plurality of energy storage power supply units are connected in a grid-connected manner, an optical storage power supply system in which a plurality of photovoltaic power supply units and an energy storage power supply system are connected in a grid-connected manner, a wind power generator set in which a plurality of wind power generators are connected in a grid-connected manner, a wind power generator set, or an optical wind power storage power generation unit in which a plurality of wind power generators are connected in a grid-connected manner, or the like. At the moment, the controller in the power supply system can be a subarray controller, a subarray data acquisition, box transformer substation measurement and control device, a source control terminal, a new energy panoramic monitoring terminal, or a box transformer substation all-in-one measurement and control device and the like. Correspondingly, the collection and/or control object of the controller may be voltage and/or current information of nodes such as a bus bar (or a grid-connected point) of a plurality of power supply units, a step-up transformer of a power supply unit, a grid-connected transformer (such as a box-type transformer), a photovoltaic inverter, an energy storage converter, a wind power converter or a charging pile, and the collection and/or control object may be specifically determined according to an actual application scenario, and is not limited herein. Similarly, in a photovoltaic power station, an energy storage power station, a photovoltaic power storage station, a wind power plant or a wind power storage station, the power supply system may be a photovoltaic power supply system in which a plurality of photovoltaic power supply units are connected to the grid, an energy storage power supply system in which a plurality of energy storage power supply units are connected to the grid, a photovoltaic power supply system in which a plurality of photovoltaic power supply units and an energy storage power supply system are connected to the grid, a wind power supply system or a wind energy storage power supply system in which a plurality of photovoltaic power supply units and an energy storage power supply system are connected to the grid, or the like. At this time, the controller in the power supply system may be a power station controller, a power station power controller, a power station coordination controller, a power station frequency modulation controller, or a source network load coordination device, etc. Correspondingly, the collection and/or control object of the controller may be voltage and/or current information of nodes such as bus bars (or grid-connected points) of a plurality of power supply units, a subarray controller, a subarray data collector, or a subarray control terminal, and may be specifically determined according to an actual application scenario, which is not limited herein. Optionally, in the wind power plant or the wind power storage station, the power supply system may be a photovoltaic power supply system in which a plurality of wind power supply units are connected in a grid-connected manner, or a wind power storage and supply system in which a plurality of wind power supply units and an energy storage and supply system are connected in a grid-connected manner. At the moment, a controller in the power supply system can be a box transformer substation protection measurement and control device, a box transformer substation all-in-one measurement and control device, a source control terminal, a new energy panoramic monitoring terminal and the like. Correspondingly, the collection and/or control object of the controller may be the voltage and/or current information of nodes such as a bus bar (or a grid-connected point) of a plurality of power supply units, a step-up transformer of a wind power supply unit, a grid-connected transformer (such as a box-type transformer), a fan master control, or a wind power converter, and may be specifically determined according to an actual application scenario, which is not limited herein. In the microgrid, the power supply system can be a photovoltaic power supply system with a plurality of fuel oil generators connected in a grid-connected mode, or a power supply system with a plurality of distributed power sources connected in a grid-connected mode. At this time, the controller in the power supply system may be a microgrid controller, a microgrid coordinated control device, a sub-microgrid controller, or the like. Correspondingly, the collection and/or control object of the controller may be voltage and/or current information of nodes such as a grid-connected step-up transformer, a grid-connected point switch, an energy storage converter, a Battery Management System (BMS), an inverter, a diesel generator, a wind driven generator, a load or a load switch of a power supply unit, and may be determined according to an actual application scenario without limitation.
TABLE 1
Figure BDA0003823054100000101
In the application, the controller in each power supply system reports the local power oscillation information to the superior system to trigger the superior system to perform system-level power oscillation analysis, so that the superior system can comprehensively and timely obtain systematic power oscillation information, the power supply stability of the power supply system can be ensured, the system safety of the superior system can be ensured, and the power supply stability of the power system is enhanced.
Optionally, referring to fig. 3, fig. 3 is another schematic structural diagram of the power system provided in the embodiment of the present application. As shown in fig. 3, in each power supply system, the controller may be a controller of performance forms such as a power station controller, a power station power controller, a power station coordination controller, a power station frequency modulation controller, or a source network load coordination device, at this time, there may also be a unit controller in each power supply unit in the power supply system, at this time, the unit controller may be a subarray controller, a subarray number acquisition, a box transformer measurement and control device, or a source control terminal, and the performance forms of the controller and the unit controller may be determined specifically according to an actual application scenario, which is not limited herein. It can be understood that, in the power supply system, each power supply unit may share one unit controller (in this case, the unit controller may be a subarray controller, and a subarray is a power supply unit subarray in which a plurality of power supply units are connected in a grid-connected manner), and each power supply unit may also include its own unit controller, which may be determined according to an actual scene. The controller of the power supply system may be in communication with the cell controller of the power supply unit, and in this case, the controller may be a superior controller of the cell controller. The controller of the power supply system can directly detect the voltage and/or current information of a grid-connected point of the power supply system to monitor the local power oscillation information of the power supply system, and further can control the power conversion equipment (comprising a photovoltaic inverter, a wind power converter and/or an energy storage converter) of each power supply unit in the power supply system to output power for inhibiting local power oscillation when the local power oscillation of the power supply system is obtained, so that the local power oscillation of the power supply system is inhibited.
Referring to fig. 4, fig. 4 is a schematic structural diagram of a power supply system provided in an embodiment of the present application. As shown in fig. 4, the power supply system may include a controller and one or more power supply units, where each of the one or more power supply units includes a power supply component and a power conversion device (see fig. 1, 2, or 3, and not shown in fig. 4), and the power supply component of each of the power supply units is connected to a grid-connected point of the power supply system through the power conversion device. As described in the corresponding implementation manners of fig. 1 and fig. 2, in the power supply system shown in fig. 4, the power supply component in each power supply unit may include a photovoltaic array, a wind power supply component, or an energy storage battery, and correspondingly, the power conversion device in each power supply unit may include a photovoltaic inverter, a wind power converter, or an energy storage converter. In other words, the power supply system provided by the present application may be a photovoltaic system, a wind power generation system, a light storage power generation system, a wind farm, a microgrid, and the like, and the power supply components and the power conversion devices corresponding thereto in different application scenarios or product forms may also be configured adaptively, and are flexible to operate and strong in applicability, which may specifically refer to the implementation manners corresponding to fig. 1, fig. 2, and/or fig. 3, which is not limited herein.
In some possible embodiments, in the power supply system shown in fig. 4, the controller may collect voltage and/or current information of a grid-connected point of each power supply unit, where the controller may directly connect to the grid-connected point to collect the voltage and/or current information of the grid-connected point, and may support access of an instant value of the voltage and/or current of the grid-connected point. Referring to fig. 5, fig. 5 is another schematic structural diagram of a power supply system according to an embodiment of the present disclosure. Optionally, as shown in fig. 5, the controller may also connect to a grid-connected point through a CT, and current information of the grid-connected point is collected through the CT, so that current access with a current rating of 1A or 5A may be supported. Optionally, the controller may also collect voltage information of a grid-connected point through the PT, and may support voltage access with a voltage rating of 100V to 1000V. Meanwhile, as shown in fig. 4, the controller can support interval voltage to be directly accessed without PT, namely, the controller can directly collect voltage information of a grid-connected point without introducing primary equipment PT, and the controller is flexible to operate and high in applicability.
In some possible embodiments, the controller may calculate, when obtaining the power oscillation information based on the voltage and/or current information of the grid-connected point, an incremental power for suppressing the power oscillation based on the power oscillation information, and may control the power conversion device of each of the one or more power supply units to output the first output power. As shown in fig. 5, the controller may include a power oscillation monitoring module, where the monitoring module may include analog quantity acquisition, sampling calculation, power oscillation analysis, and other functional modules, and the analog quantity acquisition-based functional module may acquire analog quantity information such as output waveforms of voltages and/or currents of a grid-connected point, and may further obtain power oscillation information and/or a power oscillation alarm through sampling calculation and power oscillation analysis. Here, the controller may support high-speed sampling (which may be implemented based on an analog quantity acquisition module) of instantaneous values of the voltage and/or current of the grid-connected point, the sampling frequency is not lower than 1200HZ, 4K or 4.8K, current sampling with a current rating of 1A or 5A, and voltage sampling with a voltage rating of 100-1000V. When the controller performs oscillation detection analysis calculations of sub/super synchronous power oscillations based on sampled data of voltage and/or current information, typical algorithms can be used including, but not limited to: fourier transform or Prony algorithm, supporting 2-50 harmonic measurement, 2.5 Hz-2500 Hz inter-harmonic measurement, 0.1 Hz-2.5 Hz low frequency oscillation monitoring, 2.5 Hz-45 Hz/super-synchronous oscillation monitoring, 55 Hz-95 Hz super-synchronous oscillation monitoring, etc. The controller detects sub/super synchronous power oscillation of each power supply unit based on an algorithm such as Prony, and the like, and can calculate and monitor (can be realized based on a sampling calculation module) the frequency and amplitude of the dominant component of A-phase voltage sub/super synchronous power oscillation, the frequency and amplitude of the dominant component of B-phase voltage sub/super synchronous power oscillation, the frequency and amplitude of the dominant component of C-phase voltage sub/super synchronous power oscillation, the frequency and amplitude of the dominant component of A-phase current sub/super synchronous power oscillation, the frequency and amplitude of the dominant component of B-phase current sub/super synchronous power oscillation, and the frequency and amplitude of the dominant component of C-phase current sub/super synchronous power oscillation according to the acquired voltage and/or current information, and sense of sub/super synchronous power oscillation, acquisition of power oscillation information and/or alarm of power oscillation are carried out according to the calculated and monitored result. As shown in fig. 5, the controller can also support continuous recording per minute through functional modules such as recording and file storage to form a recording file in a COMTRADE format, and the controller can also support information uploading of the recording file, can support various communication capabilities of uploading conventional collected data, can support communication protocols such as IEC61850, modbus, TCP, PMU, GOOSE, and the like, can adapt to requirements of data exchange, data storage, and the like of a power system, and is flexible in operation and stronger in applicability.
In some possible embodiments, the controller may further include a power oscillation suppression function module, the power oscillation suppression function module may interact with a power oscillation monitoring module (including a power oscillation analysis module), may calculate incremental power for suppressing power oscillation based on power oscillation information obtained by the power oscillation analysis module, and issue, to the power supply unit, a power oscillation suppression strategy such as a command issue frequency, an issue cycle, or an issue step required for executing a command to suppress active and/or reactive power of power oscillation. It can be understood that each functional module included in the controller is an optional functional module, and the functional modules may be divided specifically according to the function of the controller, and each functional module shown in fig. 5 is only an example, and may be determined specifically according to an actual application scenario, which is not limited herein. Here, the power oscillation suppression module in the controller may obtain the first output power output by any power supply unit based on the active and/or reactive power supplied by any power supply unit and the first incremental power for suppressing the area power oscillation, and issue an execution command (such as an output power control command of each power supply unit) of the active and/or reactive power for suppressing the power oscillation to each power supply unit through southbound communication with each power supply unit. It will be appreciated that during normal operation of the power supply system, each power supply unit may output a corresponding active and/or reactive power based on a target output power (e.g. a power system indication or a required output power) or an output power required by a load (e.g. a grid), i.e. the active and/or reactive power supplied by the respective power supply unit is the output power during normal operation of the power supply system. During normal power supply of the power supply system, the controller may control the power conversion devices of the respective power supply units in the power supply system to output corresponding active and/or reactive power based on the target output power or the output power required by the load. Specifically, the controller may obtain active power and/or reactive power required to be output by each power supply unit for normal power supply based on the target output power or the output power required by the load, superimpose incremental power for suppressing power oscillation to obtain first output power required to be output by each power supply unit, and further may control the power conversion device of each power supply unit to output the corresponding first output power of each power supply unit based on an output power control instruction (or signal) for controlling the power conversion device of each power supply unit in the power supply system to output the corresponding active power and/or reactive power, so as to meet the output power requirement for normal power supply and the power requirement for power oscillation suppression of each power supply unit, thereby suppressing power oscillation of the power supply system in controlling the output power of each power supply unit.
In the application, the controller can directly detect the voltage and/or current information of the grid-connected point of the power supply system so as to monitor the local power oscillation information of the power supply system, and then when the local power oscillation of the power supply system is obtained, the controller controls the power conversion equipment of each power supply unit in the power supply system to output the output power for inhibiting the local power oscillation so as to inhibit the local power oscillation of the power supply system, so that the power oscillation in a larger range caused by the local power oscillation of the power supply system can be avoided, and the safety of power electronic equipment such as the power supply system can be enhanced. In other words, the controller can control the power conversion equipment of each power supply unit to output the target output power, the control output of the target output power can meet the regulation requirement of the output power of the power conversion equipment and the suppression requirement of the power oscillation of the power supply system, the operation convenience of the power oscillation suppression of the power supply system can be improved, the suppression efficiency of the power oscillation of the power supply system is improved, the system safety of the power supply system is enhanced, the operation is simple, and the applicability is strong.
In some possible embodiments, as shown in fig. 4, the controller may issue a first output power control command (e.g., an execution command of active and/or reactive power for suppressing power oscillation) to the power conversion device of each power supply unit through communication with each power supply unit when obtaining the power oscillation information and/or active and/or reactive power for suppressing power oscillation. Here, the controller may include a southbound interface (or copper whisker path of the controller) for connecting to the subordinate device, and may be used to implement southbound communication with the subordinate device, including but not limited to functions of data acquisition and/or parameter setting, communication of the controller and the subordinate device, and the like. At this time, the lower-level device controlled by the controller may also be referred to as a southbound device, including but not limited to a photovoltaic inverter, a wind power converter, an energy storage converter, an electric meter, or a box-type transformer. The controller can analyze oscillation information of local power oscillation existing in the power supply system based on voltage and/or current information of a grid-connected point of the power supply system and obtain power oscillation suppression information such as increment power of oscillation suppression, and then the controller can multiplex a local communication function of the power supply system to issue a control command of active power and/or reactive power facing the power oscillation suppression function, and send an output power control command to power conversion equipment of each power supply unit of the power supply system to control the power conversion equipment of each power supply unit to output the output power facing the power oscillation suppression so as to execute the suppression of the power oscillation.
In some possible embodiments, the power conversion device of any power supply unit in the power supply system may output the first output power corresponding to any power supply unit in response to a first output power control instruction issued by the controller, that is, output power sufficient to suppress power oscillation, including the output power of the power conversion device and the incremental power for suppressing power oscillation during normal operation when the power supply unit supplies power. In the application, the power conversion equipment of each power supply unit in the power supply system has the output regulation capacity of active power and reactive power required by power oscillation suppression, can replace additionally added physical equipment such as inductance, capacitance, transformer or resistance required by traditional power oscillation suppression, fully utilizes the active power and/or reactive power regulation capacity of the power supply unit, can simplify the equipment and/or circuit deployment complexity of the power oscillation suppression of the power supply system, reduces the realization difficulty of the power oscillation suppression of the power supply system, and is simple in operation and strong in applicability.
In some possible embodiments, as shown in fig. 4 and/or fig. 5, the controller may report the power oscillation information to an upper-level system when obtaining the power oscillation information, where the upper-level system includes a power station EMS, a power station SCADA system, a power station power controller, a power grid panoramic monitoring system, a power grid safety and stability control system, a power grid wide area measurement system, and the like. The controller can report the power oscillation information to the superior system by utilizing the existing communication modes such as a copper whisker channel and the like, and has simple structure and low realization cost. In the application, the power oscillation information is reported to the superior system, so that the superior system can perform comprehensive systematic power oscillation analysis, the system safety of the superior system is ensured, the working stability of the power supply system is also ensured, and the safety of the power supply system is enhanced. In addition, in the application, the reporting of the power oscillation information can improve the effective utilization rate of the power oscillation information, and further can delete the historical power oscillation information when the local storage capacity space of the power supply system is insufficient, so that the effective utilization rate of the storage space of the power oscillation information of the power supply system is improved, and the system safety of the power supply system is enhanced.
In some possible embodiments, the controller may receive a power oscillation suppression command, where the power oscillation suppression command carries an indication of system oscillation suppression power. Optionally, the power oscillation suppression instruction may be issued by the upper level system, or may be issued by other power supply systems connected in the upper level system in a grid-connected manner (for example, issued by communication between other grid-connected power supply systems (i.e., other adjacent systems of the power supply system) in the power system to which the power supply system belongs), and may be specifically determined according to an actual application scenario, which is not limited herein. For convenience of description, the above-level system issue is exemplified below, and the area (i.e., local to the power supply system)/system-level power oscillation suppression instruction issue shown in fig. 4 and/or fig. 5 is used for controlling the power supply system to suppress local power oscillation and/or system-level power oscillation of the power system to which the power supply system belongs. In this application, the controller may issue a second output power control instruction to the power conversion device of each power supply unit in the power supply system based on the indication information of the system oscillation suppression power. The power conversion device of any power supply unit in the power supply system can respond to the second output power control instruction to output second output power for restraining system power oscillation. Optionally, when obtaining the power oscillation information, the controller may also issue a second output power control instruction to the power conversion device of each power supply unit in the power supply system based on the indication information of the system oscillation suppression power. At this time, the power conversion device of any power supply unit in the power supply system may respond to the second output power control instruction and output the second output power for suppressing the area power oscillation and the system power oscillation at the same time, which may be determined according to an actual application scenario, and is not limited herein. Here, the second output power output by any one of the power supply units may be obtained from active and/or reactive power supplied by any one of the power supply units and a second incremental power for suppressing system power oscillation, where the second incremental power is obtained from the first incremental power and/or the system oscillation suppression power. In the present application, a controller (for example, a functional module for suppressing power oscillation in the controller shown in fig. 5) may obtain, based on a requirement of system oscillation suppression power, a magnitude of output power of a power conversion device in each power supply unit for system power oscillation suppression in combination with an active and/or reactive capacity of each power supply unit, and may further instruct, based on issuing of an output power control instruction of the power conversion device of each power supply unit, the power conversion device of each power supply unit to output a target output power, where the target output power includes both an output power of each power supply unit for supplying power and an incremental power for suppressing local power oscillation and/or system power oscillation, so as to implement system-level power oscillation suppression, enhance operating stability and system safety of a power supply system, and have the advantages of simple operation and strong applicability.
In some possible embodiments, as shown in fig. 3 (not shown in fig. 4 and 5), a unit controller may be further disposed in each power supply unit in the power supply system (or each power supply unit shares one unit controller, which is not limited herein), and the controller may be configured to issue a power output scheduling instruction to the unit controller of each power supply unit, and schedule the unit controller of each power supply unit to issue the first output power control instruction or the second output power control instruction to the power conversion device of the power supply unit. In the application, based on the communication between the controller and the unit controllers of the power supply units, the power converter devices of the power supply units can be controlled to output the target output power by means of the unit controllers of the power supply units, at the moment, the controller can be a superior controller of the unit controller and can be adapted to controllers of application scenes such as power stations, power grids, new energy stations and the like, the expression form of the controller is more flexible, and the applicability is stronger.
In some possible embodiments, the controller may further receive a power oscillation monitoring instruction issued by the upper level system, where the power oscillation monitoring instruction is used to instruct the controller to feed back power oscillation information of a specified frequency band. The controller may feed back the power oscillation information to the upper system when the power oscillation information is obtained and the frequency of the power oscillation information is within the predetermined frequency band. In the present application, in consideration of performance and resource limitations of a local controller of a power supply system, the controller does not monitor all power oscillation information required by a superior system in the power supply system, and generally only part of typical information, including part of voltage and/or current information, is monitored by the controller. The superior system can issue detection information of a designated frequency band according to the requirement of the dynamic change of the system, the controller can respond to the feedback of the power oscillation information of the designated frequency band of the superior system, the effective utilization rate of the monitoring system of the power oscillation information of the system can be improved, the suppression efficiency and the resource utilization rate of the power oscillation of the system are enhanced, and the working stability and the system safety of the power supply system and the superior system are enhanced.
In some possible embodiments, as shown in fig. 4 and/or fig. 5, a grid-connected transformer may be further included in the power supply system, and the power conversion devices of the power supply units are connected in parallel to the grid-connected transformer through the grid-connected point. Optionally, the grid-connected transformer may be a box-type transformer, may be a double-winding or double-split transformer, may be a multi-winding transformer, and the like, and may be specifically determined according to an actual application scenario, which is not limited herein. The controller can acquire input/output (I/O) parameters (such as I/O parameters of a position of a breaker or a disconnecting link of the transformer) of the grid-connected transformer, realize measurement and control and/or protection of the grid-connected transformer based on the I/O parameters of the grid-connected transformer and/or voltage and/or current information of a grid-connected point, reduce the difficulty in realization of measurement and control and/or protection of a power supply system, and enhance the safety of the power supply system.
In some possible embodiments, in order to better adapt to different application scenarios or different product forms of power systems and/or representations of controllers in the power systems, the controller may also separately deploy, according to a common point of functional characteristics of the power systems in the related product forms, functions of acquiring voltage and/or current information at a point of connection of the power systems by the controller and issuing an execution command of active and/or reactive power for suppressing power oscillation, where the controller communicates with the southbound communication device, in two controllers (for example, two different Central Processing Units (CPUs)), where the two controllers may have partial functions that are relatively independent from each other or partially function with each other, and may better adapt to deployment and control requirements of each power system in the current power system, and the applicability is stronger.
Referring to fig. 6, fig. 6 is another schematic structural diagram of the power supply system provided in the embodiment of the present application. As shown in fig. 6, the controller includes a first controller (e.g., the controller 1 shown in fig. 6) and a second controller (e.g., the controller 2 shown in fig. 6), where the controller 1 may include a common acquisition module for acquiring voltage and/or current information of a point-to-point (or a collection point) of the upper power supply system. The controller 1 may include a power oscillation analysis module, and may obtain local power oscillation information of the power supply system based on the voltage and/or current information of the grid-connected point obtained by the common acquisition module, and further may transmit the obtained power oscillation information to the power oscillation suppression function module. The functional module for suppressing power oscillation can directly or indirectly issue an active and/or reactive execution command for suppressing power oscillation to power converters (such as a photovoltaic inverter, a wind power converter, an energy storage converter and the like) in each power supply unit through a southbound communication interface or channel. The controller 1 may be configured to obtain power oscillation information of the power supply system based on the voltage and/or current information of the grid-connected point, and transmit the power oscillation information to the power oscillation suppression module of the controller 2. The controller 2 may control the power conversion device of each power supply unit to output the first output power of each power supply unit based on communication between the common communication module and each power supply unit when the power oscillation suppressing module obtains the power oscillation information of the power supply system. The power oscillation suppression module in the controller 1 or the controller 2 may obtain an oscillation analysis result of the oscillation analysis module (if the power oscillation suppression module and the power oscillation analysis module are not in the same controller, the oscillation analysis result may be obtained through communication between the controllers), and the power oscillation suppression module calculates incremental power (including incremental active and/or reactive power) required for suppressing power oscillation by using a power oscillation suppression related algorithm, in combination with active and/or reactive capacity of each power supply unit, and capability (upper limit of output power of the power supply unit, active and/or reactive output range, and the like) limitation information of each power supply unit, and sends an output power control instruction to each power supply unit. In the application, the acquisition of voltage and/or current information of a grid-connected point and the control of the output power of the power conversion equipment in each power supply unit are separately deployed in different controllers, and meanwhile, the first controller and the second controller can support the detection of power oscillation information of a system, so that the deployment requirements of the controllers in different product forms can be adapted, the operation is more flexible, and the applicability is stronger.
In some possible embodiments, after the power oscillation suppressing function module in the second controller (e.g., the controller 2 shown in fig. 6) obtains the active power and/or the reactive power for suppressing the power oscillation, the power oscillation suppressing function module may issue a first output power control command or a second output power control command directly or based on communication between the common communication module and each power supply unit to the power conversion device of each power supply unit in the plurality of power supply units, or issue a power output scheduling command to the unit controller of each power supply unit to control the power conversion device of each power supply unit in the plurality of power supply units to output the first output power or the second output power of each power supply unit. In the application, the second controller can directly or indirectly interact with the unit controllers or the power conversion devices of the power supply units through the communication network to realize the output power control of the power conversion devices of the power supply units, and the power conversion device can be adapted to product form deployment such as a source control terminal of a power supply system, and is simple to operate and high in applicability.
In some possible embodiments, the controller 1 and/or the controller 2 may report the power oscillation information to an upper system when obtaining the power oscillation information. The superior system comprises a power station EMS, a power station SCADA system, a power station power controller, a power grid panoramic monitoring system, a power grid safety and stability control system, a power grid wide area measurement system and the like. In the present application, the first controller and/or the second controller (for example, the controller 1 of fig. 6 and/or the controller 2 described above) may both implement reporting of the power oscillation information, so that product selectivity and deployment flexibility of the first controller and/or the second controller are enhanced, and applicability is stronger.
In some possible embodiments, as shown in fig. 6, the controller 1 and/or the controller 2 may further receive a zone and/or system level power oscillation suppression command issued by the upper level system to achieve zone and/or system level power oscillation suppression. In addition, the controller 1 and/or the controller 2 may further receive a power oscillation monitoring instruction issued by the upper level system, where the power oscillation monitoring instruction is used to instruct the controller 1 and/or the controller 2 to feed back power oscillation information of a specified frequency band. The controller 1 and/or the controller 2 may feed back the power oscillation information to the upper system when the power oscillation information is obtained and the frequency of the power oscillation information is within the predetermined frequency band. In the application, the controller 1 and/or the controller 2 can report the power oscillation information, so that the product selectivity and the deployment flexibility of the controller 1 and/or the controller 2 are enhanced, the detection and reporting of the power oscillation information are more flexible, the information feedback is more timely, and the safety of a power supply system is further enhanced.
In some possible embodiments, as shown in fig. 6, the controller 1 may further collect an I/O parameter of the grid-connected transformer based on a functional module for implementing measurement and control and/or protection of the grid-connected converter, and implement measurement and control and/or protection of the grid-connected transformer based on the I/O parameter of the grid-connected transformer and/or voltage and/or current information of a grid-connected point. The controller 2 may further include a communication management module and an energy management system, the communication management module may perform interactive communication with power conversion devices in power supply units such as photovoltaic inverters, wind power converters, and/or energy storage converters in southbound devices based on protocols such as ethernet, power line carrier or RS-485, and may collect information such as active power, reactive power, a-phase voltage effective value, B-phase voltage effective value, C-phase voltage effective value, a-phase current effective value, B-phase current effective value, C-phase current effective value, active power, reactive power, and apparent power of each power supply unit, and obtain power oscillation information, and then send the information to an upper-level system through ethernet to perform conventional acquisition and scheduling communication, so as to implement basic communication and information acquisition with the photovoltaic inverters, the wind power converters, and the energy storage converters.
In the application, the controller 1 can realize the acquisition of I/O parameters of a grid-connected transformer and/or voltage and/or current information of a grid-connected point, the measurement, control and/or protection of the box transformer are integrated with the power oscillation analysis function of a power supply system, and the functional modules for efficiently multiplexing the current, voltage and I/O acquisition are very close to the design idea and wiring of the current new energy power supply unit (photovoltaic power supply unit, wind power supply unit and/or energy storage power supply unit). The controller 2 can realize basic communication and information acquisition with the photovoltaic inverter, the wind power converter and the energy storage converter, the controller 1 and the controller 2 can be designed corresponding to data collectors of power supply systems with different expression forms, extra devices are not required to be arranged for power oscillation suppression of the power supply systems, flexibility and efficiency of the power oscillation suppression are improved, the structure is simple, and applicability is strong.
Referring to fig. 7, fig. 7 is a schematic flowchart of a power oscillation suppression method of a power supply system according to an embodiment of the present application. The power oscillation suppression method of the power supply system provided in the embodiment of the present application (hereinafter, referred to as the method provided in the embodiment of the present application) is applicable to the power supply system provided in the embodiment, and may be executed by a controller in the power supply system, where product forms or types of the controller may be described with reference to the embodiment, and are not described again here. The method provided by the embodiment of the present application will be described below by taking a controller as an execution subject. As shown in fig. 7, a method provided in an embodiment of the present application may include the following steps:
s601, collecting voltage and/or current information of a grid-connected point of a power supply system.
In some possible embodiments, the controller may collect voltage and/or current information of a grid-connected point of each power supply unit in the power supply system to monitor power oscillations occurring in the power supply system based on the collected voltage and/or current information. The controller may directly acquire voltage and/or current information of a grid-connected point, and it may be understood that the acquired voltage and/or current information of the grid-connected point is an output voltage waveform and/or an output current waveform of the grid-connected point, the controller may support access of an instantaneous value of the voltage and/or current of the grid-connected point, may support current acquisition with a current rated value of 1A or 5A, may support voltage acquisition with a voltage rated value of 100V to 1000V, and may also support acquisition of voltage and/or current information with a sampling frequency of not less than 1200HZ, specifically may support a sampling frequency of 4K or 4.8K, specifically may be set according to an actual application scenario, and is not limited herein.
S602, when power oscillation information is obtained based on voltage and/or current information of a grid-connected point, first incremental power for restraining regional power oscillation of the power supply system is obtained.
In some possible embodiments, the controller performs oscillation detection analysis of the sub/super synchronous power oscillation based on sampled data of voltage and/or current information of the grid-connected point of the power supply system, and the controller may use typical algorithms including, but not limited to: fourier transform or Prony algorithm, etc. to calculate the power oscillation information. The controller can support 2-50 times of harmonic measurement, 2.5 Hz-2500 Hz inter-harmonic measurement, 0.1 Hz-2.5 Hz low-frequency oscillation monitoring, 2.5 Hz-45 Hz sub/super-synchronous oscillation monitoring and 55 Hz-95 Hz super-synchronous oscillation monitoring. The controller detects subsynchronous/supersynchronous power oscillation of each power supply unit based on algorithms such as Prony and the like. Optionally, the controller may perform calculation and monitoring on the frequency and the amplitude of the dominant component of the a-phase voltage sub/super-synchronous power oscillation, the frequency and the amplitude of the dominant component of the B-phase voltage sub/super-synchronous power oscillation, the frequency and the amplitude of the dominant component of the C-phase voltage sub/super-synchronous power oscillation, the frequency and the amplitude of the dominant component of the a-phase current sub/super-synchronous power oscillation, the frequency and the amplitude of the dominant component of the B-phase current sub/super-synchronous power oscillation, and the frequency and the amplitude of the dominant component of the C-phase current sub/super-synchronous power oscillation, according to the acquired voltage and/or current information, and perform sensing of the sub/super-synchronous power oscillation, acquisition of power oscillation information, and/or alarm of the power oscillation according to the calculation and monitoring result. It is understood that the calculation of the parameters of the sub/super-synchronous power oscillation of each power supply unit is only an example, and includes, but is not limited to, the calculation of the parameters of each power supply system, and any parameter that can be used for monitoring the power oscillation may be applicable, and is not limited herein.
In some possible embodiments, the controller may calculate, when obtaining the power oscillation information based on the voltage and/or current information of the grid-connected point, an incremental power for suppressing the power oscillation based on the power oscillation information, and may further control the power conversion device of each of the one or more power supply units to output the first output power. The controller may acquire analog quantity information such as output waveforms of voltages and/or currents of the grid-connected point, and may further obtain the incremental power (i.e., the first incremental power) for suppressing the power oscillation through calculation and monitoring results including, but not limited to, a frequency and an amplitude of a-phase voltage sub/super-synchronous power oscillation, a frequency and an amplitude of a B-phase voltage sub/super-synchronous power oscillation, and a frequency and an amplitude of a C-phase voltage sub/super-synchronous power oscillation of each power supply unit. It is understood that the incremental power may include active and/or reactive power for suppressing sub/super synchronous power oscillation of the power supply system, and the incremental power may be superimposed on the active and/or reactive power supplied by the power conversion device of each power supply unit to obtain a target output power required by the power conversion device of each power supply unit, which can satisfy the power supply requirement and suppress the power oscillation of the power supply system. It can be understood that after the controller obtains the power oscillation information based on the voltage and/or current information of the grid-connected point collected by itself, the controller suppresses the power oscillation of the power supply system by controlling the output power of the power conversion device of each power supply unit in the power supply system, so as to achieve suppression of the local power oscillation of the power supply system. In an electric power system (a power grid system or a new energy station) accessed by a plurality of power supply systems in a grid-connected mode, the local power oscillation suppression of each power supply system can suppress or relieve the power oscillation of the electric power system, so that the system safety of the electric power system and each power supply system in the electric power system can be guaranteed, the operation is simple, and the applicability is high.
S603, reporting the power oscillation information to the superior system.
Optionally, in some possible embodiments, the controller may report the power oscillation information to an upper-level system when obtaining the power oscillation information, where the upper-level system includes a power station EMS, a power station SCADA system, a power station power controller, a power grid panoramic monitoring system, a power grid safety and stability control system, a power grid wide area measurement system, or the like. The controller can report the power oscillation information to the superior system by utilizing communication configurations such as a copper whisker channel and the like, and has simple structure and low realization cost. In the application, the power oscillation information is reported to the superior system, so that the superior system can perform comprehensive systematic power oscillation analysis, the system safety of the superior system is ensured, the working stability of the power supply system is also ensured, the safety of the power supply system is enhanced, and the effective utilization rate of the power oscillation information can be improved.
Optionally, in some possible embodiments, the controller may receive a power oscillation monitoring command issued by the upper-level system, where the power oscillation monitoring command is used to instruct the controller to feed back power oscillation information of a specified frequency band. The controller may feed back the power oscillation information to the upper system when the power oscillation information is obtained and the frequency of the power oscillation information is within the predetermined frequency band. In the application, it is not possible for the controller to monitor all the power oscillation information required by the superordinate system, considering the performance and resource limitations of the controller, but generally only part of the typical information, including part of the voltage and/or current information, can be monitored by the controller. The superior system can issue detection information of a designated frequency band according to the requirement of the dynamic change of the system, the controller can respond to the feedback of the power oscillation information of the designated frequency band of the superior system, the effective utilization rate of resources for monitoring the power oscillation of the power supply system by the controller can be improved, the suppression efficiency and the resource utilization rate of the power oscillation of the system are enhanced, and the working stability and the system safety of the power supply system and the superior system can be enhanced.
And S604, receiving a power oscillation suppression command, wherein the power oscillation suppression command carries indication information of system oscillation suppression power.
Optionally, in some possible embodiments, the controller may receive a power oscillation suppression instruction, where the power oscillation suppression instruction carries information indicating the system oscillation suppression power. Optionally, the power oscillation suppression instruction may be issued by the upper-level system, or may be issued by other power supply systems connected to the upper-level system in a grid-connected manner (for example, issued by communication between other grid-connected power supply systems (that is, other adjacent systems of the power supply system) in the power system to which the power supply system belongs), and may be specifically determined according to an actual application scenario, which is not limited herein. For convenience of description, the following example will be described by taking the upper-level system issue as an example. The indication information of the system oscillation suppression power can be used for triggering the controller to issue a second output power control instruction to the power conversion equipment of each power supply unit in the power supply system, and the power conversion equipment of any power supply unit in the power supply system can respond to the second output power control instruction and output second output power for suppressing system power oscillation. Here, the second output power output by any one of the power supply units may be obtained from active and/or reactive power supplied by any one of the power supply units and a second incremental power for suppressing system power oscillation, where the second incremental power is obtained from the first incremental power and/or the system oscillation suppression power. Optionally, the system oscillation suppression power may be issued by the upper-level system for instruction, and is used to suppress system-level power oscillation of the power system to which the power supply system belongs.
And S605, controlling the power conversion equipment of each power supply unit in one or more power supply units connected in a grid-connected mode in the power supply system to output target output power.
In some possible embodiments, the target output power output by each power supply unit controlled by the controller may be the first output power or the second output power, and accordingly, a local power oscillation (or regional power oscillation) of the power supply system or a system-level power oscillation of the power system to which the power supply system belongs may be realized.
In some possible embodiments, the controller may issue a first output power control command (such as an execution command of active and/or reactive power for suppressing power oscillation) to the power conversion device of each power supply unit through communication with each power supply unit when obtaining the power oscillation information and/or active and/or reactive power for suppressing power oscillation. The controller can analyze oscillation information of local power oscillation existing in the power supply system based on voltage and/or current information of a grid-connected point of the power supply system, and after power oscillation suppression information such as increment power of oscillation suppression is obtained, a local communication function of the multiplexing power supply system issues an active and/or reactive power control command facing the power oscillation suppression function, and the output power control command issued by the controller to each power supply unit of the power supply system is sent to a power conversion device of each power supply unit to control the power conversion device of each power supply unit to output power facing the power oscillation suppression so as to execute the suppression of power oscillation. The controller can obtain the first output power output by any power supply unit based on the active and/or reactive power supplied by any power supply unit and the first incremental power for restraining the regional power oscillation, and issue an execution command (such as an output power control command of each power supply unit) of the active and/or reactive power for restraining the power oscillation to each power supply unit through southbound communication with each power supply unit.
It will be appreciated that during normal operation of the power supply system, each power supply unit may output a corresponding active and/or reactive power based on a target output power (e.g. a power system indication or a required output power) or an output power required by a load (e.g. a grid), i.e. the active and/or reactive power supplied by the respective power supply unit is the output power during normal operation of the power supply system. During the normal power supply process of the power supply system, the controller may control the power conversion devices of the respective power supply units in the power supply system to output corresponding active and/or reactive power based on the target output power of the power conversion devices of the respective power supply units or the output power required by the load. Specifically, the controller may obtain active power and/or reactive power required to be output by each power supply unit for normal power supply based on the target output power or the output power required by the load, superimpose incremental power (for example, first incremental power) for suppressing power oscillation to obtain first output power required to be output by each power supply unit, and further may control the power conversion device of each power supply unit to output the corresponding first output power of each power supply unit based on an output power control instruction (or signal) for controlling the power conversion device of each power supply unit in the power supply system to output the corresponding active power and/or reactive power, so as to meet the output power requirement for normal power supply and the power requirement for power oscillation suppression of each power supply unit, thereby suppressing power oscillation of the power supply system in controlling the output power of each power supply unit. In other words, the controller may directly detect voltage and/or current information of a grid-connected point of the power supply system to monitor local power oscillation information of the power supply system, and may further control the power conversion devices of each power supply unit in the power supply system to output power for suppressing the local power oscillation when the local power oscillation occurs in the power supply system, so as to suppress the local power oscillation of the power supply system, thereby avoiding a wider range of power oscillation caused by the local power oscillation of the power supply system, and enhancing safety of power electronic devices such as the power supply system. The controller controls the power conversion equipment of each power supply unit to output target output power, the control output of the target output power can meet the regulation requirement of the output power of the power conversion equipment and the suppression requirement of power oscillation of the power supply system, the operation convenience of power oscillation suppression of the power supply system can be improved, the suppression efficiency of the power oscillation of the power supply system is improved, the system safety of the power supply system is enhanced, the operation is simple, and the applicability is strong. The power conversion device of any power supply unit in the power supply system can respond to a first output power control instruction issued by the controller and output a first output power corresponding to any power supply unit, namely output a power enough to suppress power oscillation, including the output power of the power conversion device and the incremental power for suppressing power oscillation in the normal operation process when the power supply unit supplies power.
Optionally, in some possible embodiments, the controller may further issue a second output power control instruction to the power conversion device of each power supply unit in the power supply system based on the indication information of the system oscillation suppression power. And the power conversion equipment of any power supply unit in the power supply system can respond to the second output power control instruction and output second output power for restraining system power oscillation. Optionally, when obtaining the power oscillation information, the controller may issue a second output power control instruction to the power conversion device of each power supply unit in the power supply system based on the indication information of the system oscillation suppression power. At this time, the power conversion device of any power supply unit in the power supply system may respond to the second output power control instruction and output the second output power for suppressing the area power oscillation and the system power oscillation at the same time, which may be determined according to an actual application scenario, and is not limited herein. Here, the second output power output by any one of the power supply units may be obtained from active and/or reactive power supplied by any one of the power supply units and a second incremental power for suppressing system power oscillation, where the second incremental power is obtained from the first incremental power and/or the system oscillation suppression power. In the application, the controller can obtain the output power of the power conversion equipment in each power supply unit facing the system power oscillation suppression by combining the active and/or reactive capacity of each power supply unit based on the requirement of the system oscillation suppression power, and further can instruct the power conversion equipment of each power supply unit to output the target output power based on the issuing of the output power control instruction of the power conversion equipment of each power supply unit, wherein the target output power comprises the output power of each power supply unit for power supply and the incremental power for suppressing the local power oscillation and/or the system power oscillation, so that the system-level power oscillation suppression can be realized, the working stability and the system safety of the power supply system are enhanced, and the controller is simple to operate and high in applicability.
Optionally, in some feasible embodiments, if a unit controller is deployed in each power supply unit in the power supply system (or each power supply unit shares one unit controller, which is not limited herein), the controller may also issue a power output scheduling instruction to the unit controller of each power supply unit, and schedule the unit controller of each power supply unit to issue the first output power control instruction or the second output power control instruction to the power conversion device of each power supply unit. In the application, based on the communication between the controller and the unit controllers of the power supply units, the unit controllers of the power supply units can be used for controlling the power converter equipment of the power supply units to output target output power, at the moment, the controller can be a superior controller of the unit controller and can be adapted to controllers of application scenes such as power stations, power grids, new energy field stations and the like, the expression form of the controller is more flexible, the realization flexibility of power suppression can be improved, and the applicability is stronger.
In the application, the controller of the power supply system can achieve local regional power oscillation detection and suppression based on acquisition of voltage and/or current information of a power supply system grid-connected point, acquisition of power oscillation information and calculation of incremental power for suppressing power oscillation, and can report relevant data (such as voltage and/or current information of power oscillation) of the power oscillation to a superior system (namely a power system of a new energy field station). Meanwhile, the power supply system can be used as a subarray of a power system such as a new energy station, a power grid system and the like to automatically detect and suppress power oscillation, the probability of system-level power oscillation of the new energy station can be reduced, the configuration cost of primary equipment for suppressing the power oscillation in the power grid system-level power oscillation suppression is reduced, the stability and the economy of the power system are improved, the operation is simple, and the applicability is high.

Claims (19)

1. A power supply system is characterized in that the power supply system comprises a controller and one or more power supply units, each power supply unit comprises a power supply assembly and a power conversion device, and the power supply assemblies are connected to a grid-connected point of the power supply system through the power conversion devices;
the controller is used for collecting voltage and/or current information of the grid-connected point;
the controller is further configured to control the power conversion device of each of the one or more power supply units to output a first output power based on power oscillation information, where the power oscillation information is obtained based on voltage and/or current information of the grid-connected point;
wherein the first output power of any power supply unit is obtained by active and/or reactive power supplied by any power supply unit and first incremental power for restraining regional power oscillation.
2. The power supply system according to claim 1, wherein the controller is specifically configured to issue a first output power control instruction to the power conversion device of each of the power supply units;
the power conversion device of any power supply unit is used for responding to the first output power control instruction to output the first output power of any power supply unit.
3. The power supply system according to claim 1 or 2, wherein the controller is further configured to receive a power oscillation suppression instruction, and the power oscillation suppression instruction carries information indicating system oscillation suppression power;
the controller is further used for issuing a second output power control instruction to the power conversion equipment of each power supply unit based on the indication information of the system oscillation suppression power;
the power conversion device of any power supply unit is used for responding to the second output power control instruction to output second output power;
wherein the second output power of any power supply unit is obtained by active and/or reactive power supplied by any power supply unit and second incremental power for suppressing system power oscillation, wherein the second incremental power is obtained by the first incremental power and/or the system oscillation suppression power.
4. The power supply system according to claim 2 or 3, wherein the power supply unit further includes a unit controller therein;
the controller is used for issuing a power output scheduling instruction to the unit controller of each power supply unit and instructing the unit controller to issue the first output power control instruction or the second output power control instruction to the power conversion equipment of the power supply unit.
5. The power supply system according to any one of claims 1-4, wherein the controller is further configured to report the power oscillation information to a superior system;
the superior system comprises one of a power station energy management system EMS, a power station data acquisition and monitoring SCADA system, a power station power controller, a power grid panoramic monitoring system, a power grid safety and stability control system or a power grid wide area measurement system.
6. The power supply system of claim 5, wherein the controller is further configured to receive a power oscillation monitoring instruction issued by the upper-level system, where the power oscillation monitoring instruction is used to instruct the controller to feed back power oscillation information of a specified frequency band;
the controller is specifically configured to report the power oscillation information to the upper-level system when the power oscillation information is obtained and the frequency of the power oscillation information is within the designated frequency band.
7. The power supply system according to any one of claims 1 to 6, further comprising a grid-connected transformer, wherein the power conversion device of each power supply unit is connected in parallel to the grid-connected transformer through the grid-connected point;
the controller is further used for collecting input I/output O parameters of the grid-connected transformer and realizing measurement and control and/or protection of the grid-connected transformer based on the I/O parameters of the grid-connected transformer and/or voltage and/or current information of the grid-connected point.
8. The power supply system of any one of claims 1-6, wherein the controller comprises a first controller and a second controller;
the first controller is used for collecting voltage and/or current information of the grid-connected point;
the first controller is further used for obtaining power oscillation information of the power supply system based on the voltage and/or current information of the grid-connected point and transmitting the power oscillation information to the second controller;
the second controller is configured to control the power conversion device of each power supply unit to output the first output power of each power supply unit based on the power oscillation information.
9. The power supply system according to claim 8, wherein the second controller is further configured to issue a first output power control instruction or a second output power control instruction to the power conversion device of each power supply unit, or issue a power output scheduling instruction to the unit controller of each power supply unit, so as to control the power conversion device of each power supply unit in the plurality of power supply units to output the first output power or the second output power of each power supply unit.
10. The power supply system according to claim 8 or 9, wherein the first controller and/or the second controller is further configured to report the power oscillation information to a superordinate system.
11. The power supply system according to claim 8 or 9, wherein the first controller is further configured to collect I/O parameters of the grid-connected transformer, and implement measurement and control and/or protection of the grid-connected transformer based on the I/O parameters of the grid-connected transformer and/or voltage and/or current information of the grid-connected point.
12. The power supply system of any one of claims 1-11, wherein the power supply assembly comprises at least one of a photovoltaic array, a wind power generation assembly, or an energy storage battery, and the power conversion device comprises at least one of a photovoltaic inverter, a wind power converter, or an energy storage converter.
13. A method of suppressing power oscillations of a power supply system, the method comprising:
collecting voltage and/or current information of a grid-connected point of a power supply system;
controlling power conversion equipment of each power supply unit in one or more power supply units connected in a grid-connected mode in the power supply system to output first output power based on power oscillation information, wherein the power oscillation information is obtained based on voltage and/or current information of a grid-connected point;
wherein the first output power of any power supply unit is obtained by active and/or reactive power supplied by any power supply unit and first incremental power for restraining regional power oscillation.
14. The method according to claim 13, wherein the controlling the power conversion device of each of the one or more power supply units connected to the grid in the power supply system to output the first output power comprises:
and issuing a first output power control instruction to power conversion equipment of each power supply unit in one or more power supply units connected in a grid-connected mode in the power supply system, and triggering the power conversion equipment of each power supply unit to respond to the first output power control instruction and output the first output power of each power supply unit.
15. The method according to claim 13 or 14, characterized in that the method further comprises:
receiving a power oscillation suppression instruction, wherein the power oscillation suppression instruction carries indication information of system oscillation suppression power;
based on the indication information of the system oscillation suppression power, issuing a second output power control instruction to the power conversion equipment of each power supply unit, and triggering the power conversion equipment of each power supply unit to respond to the second output power control instruction and output second output power;
wherein the second output power of any power supply unit is obtained by active and/or reactive power supplied by any power supply unit and second incremental power for suppressing system power oscillation, wherein the second incremental power is obtained by first incremental power and/or system oscillation suppression power.
16. The method according to claim 14 or 15, further comprising:
and issuing a power output scheduling instruction to the unit controller of each power supply unit, and instructing the unit controller to issue the first output power control instruction or the second output power control instruction to the power conversion equipment of the power supply unit.
17. The method according to any one of claims 14-16, further comprising:
reporting the power oscillation information to an upper-level system;
the superior system comprises one of a power station energy management system EMS, a power station data acquisition and monitoring SCADA system, a power station power controller, a power grid panoramic monitoring system, a power grid safety and stability control system or a power grid wide area measurement system.
18. The method of claim 17, further comprising:
receiving a power oscillation monitoring instruction issued by the superior system, wherein the power oscillation monitoring instruction is used for indicating the controller to report power oscillation information of a specified frequency band;
the reporting of the power oscillation information to the superior system includes:
and when the power oscillation information is obtained and the frequency of the power oscillation information is within the specified frequency band, reporting the power oscillation information to the superior system.
19. An electrical power system, comprising: a control system and a plurality of power supply systems as claimed in any one of claims 1 to 12;
the control system comprises one of the power station energy management system EMS, the power station data acquisition and monitoring SCADA system, the power station power control system, the power grid panoramic monitoring system, the power grid safety and stability control system or the power grid wide area measurement system.
CN202211048934.3A 2022-08-30 2022-08-30 Power supply system, power oscillation suppression method for power supply system, and power system Pending CN115425661A (en)

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Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN116238379A (en) * 2023-03-27 2023-06-09 阿维塔科技(重庆)有限公司 Charging adjustment method and device

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN116238379A (en) * 2023-03-27 2023-06-09 阿维塔科技(重庆)有限公司 Charging adjustment method and device
CN116238379B (en) * 2023-03-27 2023-09-26 阿维塔科技(重庆)有限公司 Charging adjustment method and device

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